The coverage has prompted a lot of discussion, because in the absence of facts, CNN has served lots of speculation for three weeks about what might have gone wrong. Some media critics and Fox News' Bill O'Reilly have questioned the approach, but the style has has connected with many viewers.

In weekday prime time, CNN was up 35 percent in total viewers and 71 percent the 25-to-54 age group, which is most important to news advertisers. In the 25-to-54 age group in weeknight prime time, CNN averaged 240,000 viewers to MSNBC’s 201,000.

The March news lineup also included coverage of Ukraine and the Washington state mudslide, but CNN spent a lot of time on Flight 370 in weekday prime time. The coverage boosted programs. In total viewers, Anderson Cooper’s “AC360” was up 36 percent from a year ago, and “Erin Burnett OutFront” was up 48 percent.

CNN also drew closer to Fox News, the ratings leader in cable news, in the 25-to-54 age group. CNN highlighted Monday-Sunday figures to illustrate the contest. In February prime time, Fox News averaged 317,000 viewers to CNN’s 136,000. In March, Fox News pulled in 309,000 to CNN’s 231,000. MSNBC had 197,000.

In all of cable for total day rankings in March, Fox News Channel was fourth while CNN was No. 23 and MSNBC was No. 29.

Fox News highlighted first quarter ratings, which showed its huge advantage. In prime time, Fox News averaged 1.8 million viewers to MSNBC’s 683,000 and CNN’s 498,000. Fox News was up 4 percent from a year ago while MSNBC was down 10 percent and CNN was off 16 percent.

In the 25-to-54 age group, Fox News averaged 293,000 to MSNBC’s 217,000 and CNN’s 169,000. Fox News was up 5 percent from last year while MSNBC was down 4 percent and CNN was off 3 percent.

Fox News also had the five most-watched programs in cable news for the first quarter: “The O’Reilly Factor” with 2.8 million, “The Kelly File” with 2.2 million, “The Five” with 2.1 million, “Special Report with Bret Baier” with 2.1 million and “On the Record With Greta Van Susteren” with 1.8 million.